DIR-868L unstable NAS

Hi,
I'm experiencing NAS-related problem, that collapses router (looses connectivity, needs to be rebooted).
Configuration: DIR-868L Release 2020.3, Entware SSH (SSH service status not influencing behaviour, Entware catalog on HDD mounted as /opt)
Seagate USB3 external HDD, 2 NTFS volumes, Open NTFS-3G driver (default), enabled Spin down each HDD when idle
Related service running: NAS, miniDLNA (media index on 1st NTFS volume)
Connected client: MacOS Catalina
Reproduction: operations on...

DIR-868L unstable NAS